package com.wzd.service.wechat.utils;

import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.Arrays;

import org.apache.commons.codec.digest.DigestUtils;

import com.wzd.service.wechat.redpack.RedPack;
import com.wzd.utils.Configs;

/**
 * 签名工具类
 * 
 * @author WeiZiDong
 *
 */
public class SignUtil {
	/**
	 * 红包签名
	 */
	public static String signRedPack(RedPack redPack) {
		StringBuffer sign = new StringBuffer();
		sign.append("act_name=").append(redPack.getAct_name());
		sign.append("&client_ip=").append(redPack.getClient_ip());
		sign.append("&mch_billno=").append(redPack.getMch_billno());
		sign.append("&mch_id=").append(redPack.getMch_id());
		sign.append("&nonce_str=").append(redPack.getNonce_str());
		sign.append("&re_openid=").append(redPack.getRe_openid());
		sign.append("&remark=").append(redPack.getRemark());
		sign.append("&send_name=").append(redPack.getSend_name());
		sign.append("&total_amount=").append(redPack.getTotal_amount());
		sign.append("&total_num=").append(redPack.getTotal_num());
		sign.append("&wishing=").append(redPack.getWishing());
		sign.append("&wxappid=").append(redPack.getWxappid());
		sign.append("&key=").append(Configs.get("passkey"));
		return DigestUtils.md5Hex(sign.toString()).toUpperCase();
	}

	/**
	 * 验证签名
	 * 
	 * @param signature
	 * @param timestamp
	 * @param nonce
	 * @return
	 */
	public static boolean checkSignature(String signature, String timestamp, String nonce) {
		String[] arr = new String[] { Configs.sToken, timestamp, nonce };
		// 将token、timestamp、nonce三个参数进行字典排序
		Arrays.sort(arr);
		StringBuilder content = new StringBuilder();
		for (int i = 0; i < arr.length; i++) {
			content.append(arr[i]);
		}
		MessageDigest md = null;
		String tmpStr = null;

		try {
			md = MessageDigest.getInstance("SHA-1");
			// 将三个参数字符串拼接成一个字符串进行sha1加密
			byte[] digest = md.digest(content.toString().getBytes());
			tmpStr = byteToStr(digest);
		} catch (NoSuchAlgorithmException e) {
			e.printStackTrace();
		}

		content = null;
		// 将sha1加密后的字符串可与signature对比
		return tmpStr != null ? tmpStr.equals(signature.toUpperCase()) : false;
	}

	/**
	 * 将字节数组转换为十六进制字符串
	 *
	 * @param byteArray
	 * @return
	 */
	private static String byteToStr(byte[] byteArray) {
		String strDigest = "";
		for (int i = 0; i < byteArray.length; i++) {
			strDigest += byteToHexStr(byteArray[i]);
		}
		return strDigest;
	}

	/**
	 * 将字节转换为十六进制字符串
	 *
	 * @param mByte
	 * @return
	 */
	private static String byteToHexStr(byte mByte) {
		char[] Digit = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F' };
		char[] tempArr = new char[2];
		tempArr[0] = Digit[(mByte >>> 4) & 0X0F];
		tempArr[1] = Digit[mByte & 0X0F];

		String s = new String(tempArr);
		return s;
	}
}
